Light emitting diodes (LEDs) are increasingly used for lighting applications including home and office lighting fixtures. LEDs are current fed devices and as such control of the current allows modulation of the output light intensity. Further, LEDs have a relatively small time constant meaning that certain variations in current will quickly impact the output light intensity. Such low frequency variations may manifest as a flicker which often is unpleasant to the human eye.
Conventional LED circuits have included a power source and a resistor in addition to the LED. Unfortunately with these supply types, a large fraction of the power is dissipated in the resistor and therefore the circuit is not efficient. As LEDs increase in power output and increase in current requirements, the power dissipated in the resistor increases, thus more power is wasted.